[The Listserve] A squirrel in the tree of knowledge

One of my favourite quotes about science comes from Albert Einstein: “[A]ll our science, measured against reality, is primitive and childlike – and yet it is the most precious thing we have.”

When I try to communicate what science is, I like to use the following metaphor.

Science is like a living tree. In the trunk we find theories that have survived all previous seasons and each pruning: they have been corroborated by lots of evidence and independent tests; they receive a probability extremely close to 100%. The branches are younger, less well confirmed, but highly probable still. The twigs are relatively young and many of them will have to be pruned during the following seasons: they will be falsified by further evidence, or simply rendered much less probable than a competing branch. Most twigs will never turn into the wood that textbooks are made of. But it's impossible to predict which are the ones that will make it: we can only observe how the tree develops and prune redundancies when time comes. The multitudes of individual articles that appear, day in day out, form the leaves: all of them will fall off, fertilizing the soil and feeding the roots of the tree of science. Though short-lived and less probable than other structures, they are vital to provide energy for the rest of the tree.
The tree flourishes best when other organisms live among its roots: curiosity and a thirst for cures and practical solutions. But most of all, the tree needs water: money for science comes from the environment. There are many external influences on the tree. Society is like the weather: when it's sunny with soft rains of Spring, the tree will prosper, but when it becomes stormy, entire branches may break off and when there is no rain, the tree withers.
Never mistake the rustling of the leaves for science: it's ephemeral. Nor mistake the trunk for science: without roots and leaves, the wood is dead. More than anything else, science is an ongoing process, deeply entwined with its surroundings. Science is the living of the tree.

I'm pretty sure that I didn't invent this metaphor – after all, the 'tree of knowledge' is even a biblical motif. I may have read it somewhere specifically applied to science, but if so I've forgotten the source. (Please tell me if you remember reading a similar presentation!)

It sure looks like the tree of science has some stormy weather ahead. We've all rested in its shade and enjoyed its fruits, but are we willing to defend it? If so, you might consider joining the ""March for Science"" on April 22nd.

As a philosopher of science, I often feel like a red squirrel frolicking in its crown, but also defensive of my habitat. That's why I will join the Belgian sister march in Brussels.